A driver of a street sweeper moving "extremely slowly" on a highway in Mississauga is facing charges for allegedly keeping open liquor in his vehicle, Ontario Provincial Police said Sunday. 

Sgt. Kerry Schmidt, spokesperson for the OPP's Highway Safety Division, said police received a few calls from people who saw the street sweeper driver allegedly drinking while driving on Queen Elizabeth Way last week.

Officers stopped the vehicle, observed the driver drinking "what appeared to be alcohol" inside the street sweeper and arrested him.

The man, 48, of Mississauga, has been charged with impaired driving, driving with a blood alcohol concentration over the legal limit (80 milligrams per 100 millitres of blood) and having open alcohol in a vehicle. The street sweeper was towed from the scene.

'This is pretty serious'

"This is of huge concern for us," Schmidt said on Twitter on Saturday. "It's a large, commercial, strange vehicle."

Schmidt said 33 people have died in Ontario in drug or alcohol-related crashes this year and more than 4,000 impaired driving charges have been laid.

"People are making poor decisions, poor choices, and getting into a vehicle of whatever type, and driving down the roads. People are getting hurt and people are dying. This is pretty serious," he said. 

Schmidt thanked the witnesses for reporting the driver to police.

"You have a huge part to play in road safety," he said.